I am having a real hard time trying to get a rifle to shoot decent groups. It's an emf 1874 sharps in 45-70 with a 1 in 21 twist. I am shooting a rcbs 405 grn gas checked sized in .458 and .460. Have tried RE7,3031,xmp 5744 and one other I can't remeber off hand and all with shotgun patterns[4-6"] at 100 yards.Tried slugging and came up with around .460 but kind of hard to tell with that piece of lead.Using straight wheel weights. Fedral large rifle and magnum primers.Even emailed company and they said some bores where shipped over sized. Been trying for 2 years . Any ideas guys